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为了研究球床通道内网格效应对CFD计算精度的影响,本文采用两类网格划分形式,对体心堆积结构球床通道内层流和湍流下的阻力和传热特性进行了数值计算。通过对比发现:在层流时,流道内的整体网格密度是决定阻力和传热特性计算结果精度的主要因素,在相同条件下,阻力对网格密度的依赖程度大于传热。而湍流时,决定阻力和传热特性计算结果精度的主要因素是近壁面网格数量,通过构建贴体附面层网格,能够在保证计算精度的条件下,有效地控制整体网格数量。
In order to study the effect of grid effect in CFD on the calculation accuracy of CFD, two types of grids are used in this paper to calculate the resistance and heat transfer characteristics of laminar flow and turbulent flow in the ballistic passage of CFD. The comparison shows that the overall grid density in the runner is the main factor that determines the accuracy of the calculation of resistance and heat transfer characteristics in the laminar flow. Under the same conditions, the resistance depends more on the grid density than on the heat transfer. In turbulent flow, the main factor that determines the accuracy of calculation results of resistance and heat transfer characteristics is the number of near-wall meshes. By constructing the overlay meshes, the overall mesh number can be controlled effectively with the accuracy guaranteed.